This was a randomized controlled study. The enrolled patients were divided into the experimental group (E-group) and the control group (C-group) according to the random number table method. All the participants received the traditional training for dysphagia for four weeks, five days per week, twice a day, 30 minutes each time. The E-group received the additional direct feeding training twice a day, 20 minutes each time, for a total of four weeks. All participants were evaluated using the Functional Oral Intake Scale (FOIS) and the modified V-VST before and after training. The nasogastric tube removal rate was calculated in both groups post-training.Participants
This prospective analysis enrolled 214 patients with PSD recruited consecutively from Nanjing Brain Hospital between January 2016 and September 2020.
Inclusion criteria were as follows: 1) the occurrence of a cerebrovascular accident with hemorrhagic or ischemic infarction confirmed with computed tomography or magnetic resonance imaging for approximately seven days to three months, with the course of the indwelling nasogastric tube being no more than 90 days; 2) 18–80 years old; and 3) Functional Oral Intake Scale (FOIS) evaluated as grade 1–3.
Exclusion criteria were as follows: 1) a previous neurological condition that could cause dysphagia; 2) an existing pulmonary infection at the time of admission; and 3) collaborators with severe mental or cognitive impairment.
In total, 34 patients were excluded from the study. According to the random number table method, the remaining 180 patients were divided into the experimental group (E-group) and the control group (C-group), with 90 patients in each group. Eight participants in the E-group and five in the C-group were lost to follow-up, and the follow-up rate was 92.78%. Recruitment, randomization distribution, follow-up, and analysis have been reported in a flow chart stating the number of participants at each step (Figure 1).
Modified Volume Viscosity Swallow Test (M-VVST)
The modified V-VST was performed at the patient’s bedside using liquid boluses of different viscosities (low, moderate, and high viscosity) at increasing volumes (3, 5, and 10 ml). The low viscosity was obtained by adding 1.0 g (74–78 mPa-s) of a new generation of thickener based on xanthan gum (Softia S, NUTRI Co., Ltd., Yokkaichi, Japan) to 100 ml of mineral water at room temperature; the moderate and high viscosities were obtained by adding 2.0 g (203–208 mPa-s) and 3.0 g (361–381 mPa-s), respectively, of thickener to 100 ml mineral water. The test started at moderate viscosity, and if any of the safety variables were altered, it continued with high viscosity. If no safety alterations were observed, the test continued at low viscosity and high viscosity (Figure 2). The differences between V-VST  and M-VVST were that we used a lower sip volume to begin with, different viscosities, and a new generation of thickener.
Training materials and process
- Oral sensation and motor training include oral muscle training, sucking, larynx lifting training, pharyngeal ice stimulation, empty swallowing training, and Mendelssohn training.
- Breathing and cough training was performed.
- We also performed language, writing, gesture stimulation, and pronunciation training.
- Low-frequency electrical stimulation therapy: A low-frequency electrical device named VitalStim was purchased from the United States. The neuromuscular electric stimulator was used for treatment, and the stimulation electrode was placed in the lower jaw of the patient. To stimulate the extralingual and pharyngeal muscles of the neck, the bidirectional square wave width was 700 ms, the frequency range was 30–80 Hz, and the intensity was 7–10 mA.
Direct feeding training
- Training food preparation
The training food for the experimental group was obtained by adding 1.5 g of the new generation of food texture modification based on xanthan gum (Softia G, NUTRI Co., Ltd., Yokkaichi, Japan) to 200 ml boiled water, stirred and cooled to form a hydrogel, and set aside without adding any food.
The intake of food training started from 3 to 5 ml based on the results of M-VVST, and then increased to 10 ml to 20 ml. Ingestion was stopped as soon as safety changes occurred.
The total volume started from 50 to 80 ml. It gradually increased about 60 ml each time, every two days, until the patient reached regular food intake, at which 200–300 ml is appropriate.
The patients needed to eat carefully to prevent food from entering the trachea; 30–40 min was suitable for the whole process, with sufficient rest time. If safety or efficacy changes occurred, the patient was asked to stop eating immediately.
Sitting is the ideal posture. When it was not possible, we rolled the head of the bed 30–60°, tilted the neck forward, and padded the shoulders on the hemiplegic side, and the feeder was on the healthy side.
We assisted the patient in putting food on the middle and back part of the tongue and gently pressed the tongue with the back of a spoon to stimulate swallowing. After swallowing food each time, we had the patient do empty eating several times or drink a little water (<1 ml) after each swallowing, and then we fed the second mouthful after confirming that the first one had been swallowed completely.
Functional Oral Intake Scale (FOIS)
According to the patient’s oral intake, the FOIS was used for swallowing function grade (Table 2).
Incidence of safety and efficacy changes
During the M-VVST, impaired safety of swallow signs included coughing during or after eating, voice changes, or decreased oxygen saturation ≥ 3%. Oral and pharyngeal residue and piecemeal deglutition were signs of impaired efficacy. Complaining about inability to swallow completely or repeated swallowing or aspiration after the swallow (within 1–2 min after swallowing) were residual signs in the pharynx . The incidence of safety and efficacy changes were compared between the two groups.
Rate of tube removal
The indication for removing the nasal feeding tube was as follows: If the patient could eat more than 200 ml of mushy or texture-modified food in 30–40 min each meal for three consecutive days without signs of aspiration, the nasal feeding tube could be removed.
The assessments were performed by two trained nurses who had received professional training to use the methods in terms of the basic theory and standard methods of screening for dysphagia. The training was supervised by a senior speech therapist, who had learned specialized knowledge from school, practiced for years in a standard stroke unit, and passed the National Health Professional and Technical Qualification Examination for the attending level.
Categorical variables were presented in number (percentage), continuous variable in mean ± standard deviation, and median data. Statistical analysis was performed using SPSS 25.0 software. Comparisons of continuous variables were evaluated using an independent sample t test, and comparisons of rate were assessed using the χ2 test or Fisher exact test. The Mann–Whitney U test or Wilcoxon signed-rank test was performed for the ranked data. A value of p < 0.05 was considered to be statistically significant.